How to Create Photo-Realistic Grass Visualisations for Revit Projects Using 3ds Max

Mowing the Lawn

The example below shows just how horrible the basic grass material looks when rendered in Revit.

The problem is, that the material options within Revit are very basic: Create a material, choose an image and you’re pretty much done as far as having any control over how the image is mapped.

Yes, you can change the scale and the position, as well as the glossiness and highlights, but Revit is not designed to be an advanced photo-realistic visualization tool. Materials in Revit are there to display how an object should appear in plans, sections, elevations etc. as well as contain additional information such as thermal and structural properties allowing them to be analysed. They can also be used to calculate material take-offs for quantification. So rendering plays only, a small part of their overall use.

When Revit renders the grass over a large area, you will see a ‘tiling’ pattern where the image used is repeated. In the image below you can see that the grass bitmap is darker towards the edge and this is what gives obvious repeated patterns.

But fear not, for this is where 3DS Max (part of your Building Design Suite or AEC Collection) can play a part. Yup that software which you have never bothered to look at and which many have the misconception that you need to be a 3DS Max magician and spend days shut away in a dark room with applying wizardry which no normal muggle can aspire to achieve.

Yes – 3DS Max is a beast of a package and can (in the hands of said wizard) create images which can’t be distinguished from reality, but using a few simple steps even us mortals can enhance our Revit scenes to something which doesn’t look like it was created in the 80’s.

So let’s run through the steps to create something which looks more like grass.

Create a pane and apply the grass material in Max – that already looks better doesn’t it. That’s because as well as applying the image of grass, this material also has a Bump Map set. Bump mapping is a technique in computer graphics for simulating bumps and wrinkles on the surface of an object. In the case of this material, the Bump Map is a simple black and white noise image which will create a stippled effect on what is actually a flat surface.

Step 2. Noise and Hair Modifiers

Next we can enhance the scene further by applying Noise to the physical plane. This will cause the plane to undulate giving a more realist appearance to that of normal ground (unless you are creating a crown green bowling lawn of course). Then we will simulate some 3D grass using the hair and Fur modifier.

With the plane selected, increase both the Length and Width Segments (the more segments, the finer the control over the planes surface).

Next select the Noise modifier from the drop-down. Set the modifier to Fractal and adjust the Scale and Strength as shown in the previous screen-shot.

If you render the scene at this point, you will see the effect that applying the Noise modifier has:

Now select the Hair and Fur modifier. Again use similar values to these:

NOTE: Use the Sample Screen Colour dropper when picking the Tip and Root colour. Pick colour from one of your previous renders. This will ensure that the 3D grass colour ties in with the 2D bitmap.

The Flyaway and Clumping Parameters create effects which stop the grass from being completely uniform and thus appear more lifelike.

Now give your scene another render:

Of course, this will increase the render time, but for the sake of eliminating those horrible repeated grass tile scenes – we’re worth it.

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